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Abstract

The paper presents new studies on numerical modeling (FEM) for beam-to-column
behavior under sagging and hogging bending moment when the framework is exposed to
service and unexpected loads that may cause a column loss scenario. This investigation
is focused on four bolts end-plate joints with 10 mm thickness which are proven
experimentally to have more ductile behavior than other end-plates joints (6, 8 bolts),
spite of their weakness to transfer the unexpected loads from the initial state to a residual
state of the stable equilibrium, that leads to a failure of limited floor area to adjacent
joints when tested experimentally (Saleh, 2014). FEM technique used in this research
is an extension of the previous technique and is characterized by the use of a more
sophisticated technique than the previous, discovered from the result of continuous
research and the use of all the options available in the new version of commercial
ABAQUS/CAD software. The elements are designed using multiple layers of specific
elements of a brick arranged in such a way that the mesh nodes of the tiles should
coincide with certain layers with the top of the shear inlay and in line with reinforcement,
not as the former study that used thick shell elements to model the reinforced concrete
slab with total negligence of reinforcing steel and bolts between the slap and the beam.
This investigation is very complex because of highly nonlinear effects associated with
the prediction of joint performance, such as structural imperfections, huge displacements
and large rotations, inelastic properties of steel and concrete, bonding effects between
steel and concrete, friction between end-plate and column flange and focus on the slip
between concrete and structural steel, among others which is the most difficult modelling
application. The paper addresses all these problems in addition to an evaluation of
the joint with four bolts end-plate and provides recommendations for new computer
simulation techniques (FEM). With these satisfactory results, this technique can be used
to solve many problems and difficulties facing the steel and steel-concrete composite
frames due to extraordinary events (explosions and hurricanes).